Hydroxylamine, usually in the form of salts such as hydroxylammonium sulfate, hydroxylammonium chloride or the like is widely used as a reagent for preparing various industrial, specialty and pharmaceutical chemicals. Many products containing oxime or substituted hydroxylamine groups are not susceptible to production in aqueous media. Accordingly, such materials are normally prepared by reaction of solutions of hydroxylammonium chloride in organic solvents such as methanol with the organic precursor in the presence of sufficient base to neutralize the by-product HCl. Because hydroxylammonium sulfate (also called hydroxylamine sulfate) is not soluble in methanol, however, the cheaper sulfate reagent cannot be used to prepare these materials. Many other hydroxylammonium salts are more difficult to prepare than the sulfate (made by the Raschig process) and therefore would desirably be made from the sulfate. Proposals to do so in an ion exchange, exclusion or extraction column process are contained in U.S. Pat. Nos. 4,166,842 to Tunick et al., 4,147,623 to Koff et al and 4,202,765 to Koff et al.
Hydroxylammonium salts of organic acids are made in U.S. Pat No. 2,483,252 to Tryon (1949) by reaction of hydroxylammonium sulfate or chloride with ammonium or alkali metal salts of such acid, added as such or made in situ, with the reaction temperature usually 40.degree.-70.degree. C. (see col. 2, lines 1-37).